The SwissFEL wire-scanner (WSC) composes of an in-vacuum beam-probe - motorized by a stepper motor - and an out-vacuum pick-up of the wire-signal. In SwissFEL, WSCs will absolve two main tasks: high precision measurement of the beam profile for determining the beam emittance as a complement to view-screens; routine monitoring of the beam profile under FEL operations. In order to fulfill the aforementioned tasks, the design of the in-vacuum component of the SwissFEL WSCs followed the guidelines to ensure a mechanical stability of the scanning wire at the micrometer level as well as a significative containment of the radiation-dose release along the machine thanks to the choice of metallic wires with low density and Atomic number. Beam-loss monitors have been suitably designed to ensure a sufficient sensitivity and dynamics to detect signals from scanned beams in the charge range 10-200 pC. The design, the prototyping phases, the bench and electron-beam tests - performed at SITF (Paul Scherrer Institut) and FERMI (Elettra, Trieste) - of the entire SwissFEL WSC set-up will be presented.Contribution accepted for publication in Physical Review Accelerators and Beams